Lawinenlagebericht

Central Sierra Nevada

Sierra Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 6 months ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

New snow overnight and through today along with strong winds will form slabs of wind drifted snow.  Triggering a slab avalanche will be possible below ridges and cornices, in gully features, and on open wind exposed slopes.  Sluffs of new snow could also be triggered in wind protected locations.  Make a plan for travel that avoids areas where unstable snow and the potential for avalanches may exist.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    New snow and strong winds will form slabs of wind blown snow in wind exposed locations.  Look for blowing snow, new cornices, wind pillows, and snow surface scouring as clues to where these new wind slabs have formed.  Snow surface cracking in wind deposited areas could indicate unstable wind slab.  Make a plan to avoid areas where unstable wind slabs may exist or change plans if you see signs of unstable snow.

    Wind slabs will be most problematic in near and above treeline areas, but may also form in isolated areas in below treeline terrain.   Greater hazard will exist above 8000' where the most snow fell overnight.  Wind slabs could be easier to trigger where they have formed on top of near surface facets that exist on the old snow surface.  New cornices will be forming during this storm and could be fragile.

  • Loose Dry

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    New low density storm snow fell overnight.  This snow may have problems bonding to the old snow surfaces or itself in wind protected areas.  Dry loose sluffing could occur on steep slopes and could run long distances.  These sluffs are expected to be small in size, but could take a user over rocks, cliffs, or other terrain traps if triggered. 

Avalanche Discussion

Storm snow from last night and today will be deposited on top of a variety of snow surface conditions.  Many of these surfaces on the southern half of the compass will be in good shape for additional storm loading.  Developed near surface facets have formed on wind protected northerly aspects during our prolonged dry spell.  Previous recent rain events have formed a thin surface rain crust on top of this near surface facet layer up to around 8800'.  Faceted snow grains continue to exist under this rain crust and at higher elevations where the rain crust does not exist.  This current storm is not expected to be a large enough load to cause issues on this now buried weak layer, but will have to be monitored as larger storms are in the forecast.  

Lower elevations and sun exposed slopes have experienced significant snow cover loss over the last 2-3 weeks with areas of dirt, rock, and down trees exposed.  Last nights' storm snow will be covering up some of these hazards and obstacles.  Deep open holes, open creeks, and ponded water are widespread in low lying areas, especially below 8,000'.    

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